Basics Final

• •   
• Measures the current produced when O2 diffuses across a membrane &
• it's reduced to molecular oxygen at the anode of the electrical circuit

• •   
• The current is proportional to the ppO2 in the fuel cell

• •   
• These analyzers require regular replacement of the sensory capsule

• The elec. potential for reduction of O2 results from a chemical reaction and over
• time, the reactants require replacement

• ·     
• : Oxygen
• is a nonpolar gas, but it is paramagnetic and when placed in a magnetic field,
• the gas will expand, contracting when the magnet is turned off. By switching
• the field on and off and comparing the resulting change in volume (or pressure
• or flow) to a known standard, the amount of oxygen can be measured.

·     has a gold (or platinum) cathode and a silver anode, both based in an electrolyte, separated from the gas to be measured by a semipermeable membrane. Unlike the galvanic cell, a polarographic electrode works only if a small voltage is applied to two electrodes. The amount of current that flows is proportional to the amount of oxygen present."

oximetry).

• ·     
• Oximetry depends on the observation that
• oxygenated and reduced hemoglobin differ in their absorption of red and
• infrared light (Lambert–Beer law).
• Specifically, oxyhemoglobin (HbO2) absorbs more infrared light (960 nm),
• whereas deoxyhemoglobin absorbs more red light (660 nm) and thus appears blue,
• or cyanotic, to the naked eye. The change in light absorption during arterial
• pulsations is the basis of oximetric determinations (Figure 6–22). The ratio of
• the absorptions at the red and infrared wavelengths is analyzed by a
• microprocessor to provide the oxygen saturation (SpO2) of arterial blood.
• Arterial pulsations are identified by plethysmography, allowing corrections for
• light absorption by nonpulsating venous blood and tissue.

• ·     
• Because carboxyhemoglobin (COHb) and HbO2 absorb
• light at 660 nm identically, pulse oximeters that compare only two wavelengths
• of light will register a falsely high reading in patients with carbon monoxide
• poisoning.

• ·     
• Methemoglobinemia causes a falsely low
• saturation reading when SaO2 is actually greater than 85% and a falsely high
• reading if SaO2 is actually less than 85%.

• ·     
• Bronchial intubation will usually go undetected
• by pulse oximetry in the absence of lung disease or low fraction of inspired
• oxygen concentrations (FIO2).

• ·     
• Other causes of pulse oximetry artifact include
• excessive ambient light, motion, methylene blue dye, venous pulsations in a
• dependent limb, low perfusion (eg, low cardiac output, profound anemia,
• hypothermia, increased systemic vascular resistance), malpositioned sensor, and
• leakage of light from the light-emitting diode to the photodiode, bypassing the
• arterial bed (optical shunting).

• ·     
• Increases in Exhaled CO2 can occur from:

• o  
• Hypoventilation

• o  
• Increased CO2 production

• o  
• CO2 rebreathing: Exhausted absorber, faulty
• unidirectional valves

• ·     
• Decreases in Exhaled CO2 occur from:

• o  
• Hyperventilation

• o  
• Pulmonary hypoperfusion: Decreased cardiac output,
• PE, congenital right to left shunt

• o  
• Leaking shallow breathing

• o  
• Rapid shallow breathing

• ·     
• End-expired CO2 absent:

• o  
• ETT misplacement: extubated, esophageal

• o  
• Complete tube obstruction

• o  
• Circuit disconnection

• o  
• Apnea

• o  
• Circulatory arrest

• ·     
• Diverting (Aspiration) Capnograph: continuously
• suctions gas from the breathing circuit into a sample cell within the monitor

• o  
• Prone to water precipitation into ETT

• o  
• Shouldn’t reuse

• ·     
• VERSUS: Nondiverting (Flowthrough): measures CO2
• passing through an adaptor placed in the breathing circuit

• o  
• Too heavy for a child

• o  
• Increases dead space

• o  
• Needs to be washed

• ·     
• Cuff/arm relationship: the cuff’s bladder should
• extend at least halfway around the extremity, and the width of the cuff should
• be 20% to 50% greater than the diameter of the extremity

• o  
• Influences the pressures measured

• o  
• Based on thickness of extremity, not length

• ·     
• Site

• o  
• More peripheral= SBP increases and DBP decreases

• ·     
• Hydrostatic factors

• o  
• 10cm above/below heart= 7.5 mm Hg added to or
• subtracted

• ·     
• FALSE HIGH = cuff too small

• ·     
• FALSE LOW = cuff too big

• ·     
• Hematoma/bleeding-catheter separation

• ·     
• Vasospasm

• ·     
• Arterial thrombosis

• ·     
• Embolization of air bubbles/thrombi

• ·     
• Necrosis of skin overlying catheter

• ·     
• Nerve damage

• ·     
• Infection

• ·     
• Loss of digits

• ·     
• Unintentional intra-arterial drug injection

• CAD with LV dysfunction,
• recent infarct – valvular heart disease – CHF

• Severe COP – acute
• respiratory failure

• Shock – acute renal failure –
• burns – pancreatitis

• Pericardiectomy –
• aortic-cross clamping – sitting craniotomy – portal systemic shunt – liver
• transplant

• Severe toxemia – placental
• absorption

• Ambient temperature below 21
• degree Celsius

• Anesthetic-induced
• interference with the hypothalamic thermostat

Vasodilation

• Decreases in basal metabolic
• rate

• (0-3
• Hz):
• deep sleep, deep anesthesia, or pathologic states (brain tumors, hypoxia,
• metabolic encephalopathy) –
• very low frequency due to ischemia

• (4-7 Hz): sleep and anesthesia in adults,
• hyperventilation in awake children and young adults – cortical depression

• (8-13 Hz): most common normal rhythm –
• steady wavelength seen in resting,
• awake adult with eyes closed

• (>13 Hz): when alpha rhythm is disrupted by
• excitation, a less synchronous higher frequency beta rhythm is
• seen – mental activity,
• light anesthesia

• To perform a BIS analysis, data measured from the EEG is
• calculated to a single number that correlates with the depth of
• anesthesia. 

• •       This
• value from 65-85 has been advocated as a measure of sedation,

• •       Values
• of 40-65 have been recommended for GA.

 

• Optimal use requires
• knowing what the BIS monitor IS, and also what it is NOT. 

• •       Particularly, the BIS monitor is NOT a
• MAC-meter (It cannot tell you if the patient is at MAC or not).

• •       It
• does NOT predict the likelihood of movement in response to an incision (or any
• noxious stimuli for that matter). 

• •       The
• patient could be 40 on the BIS monitor, but if you have not given enough
• narcotic, the patient can still move. 

• •       Cerebral
• ischemia can produce a loss of consciousness, and the BIS monitor may
• consequently decrease

• •       But,
• significant cerebral ischemia can occur without noticeable difference in our
• BIS monitor

• •       BIS
• is a form of EEG, but we would not use it instead of a real EEG to do a carotid
• endarterectomy

• •       Can
• be used with a propofol drip, for example, to make sure the patient is asleep

• ·     
• Diagnostic tool to evaluate certain neurologic
• disorders

• ·     
• Monitor functional integrity of sensory and motor pathways during
• surgical procedures

• o  
• Spinal fusion with instrumentation

• o  
• Spine and spinal cord tumor resection

• o  
• Brachial plexus repair

• o  
• Thoracoabdominal aortic aneurysm repair

• o  
• Epilepsy surgery

• o  
• Cerebral tumor resection

• ·     
• Extremely small amplitude (microvolts) electrical
• potentials generated by nervous tissue in response to stimulation

• o  
• Monitor by stimulating the cochlea

• o  
• Useful in assessing brainstem function in
• comatose patients

• o  
• Surgical procedures of the cerebellopontine
• angle, floor of the fourth ventricle, or fifth, seventh, or eighth cranial
• nerve

• o  
• Resistant to effects of anesthesia

• o  
• Produced by flashing light to stimulate the
• retina

• o  
• Records EPs over the occipital cortex

• o  
• Assess the integrity of the visual pathway

• o  
• Used in resection of pituitary tumors,
• craniopharyngiomas, or near optic tracts

• o  
• Monitors transmission of EPs through the sensory
• pathway

• o  
• Nerves are median, ulnar, peroneal, or posterior
• tibial

• o  
• Monitor cerebral function or ischemia

• o  
• Evaluate spinal cord function

• o  
• Assesses descending motor pathways during
• neurosurgical, orthopedic, or vascular procedures

• o  
• Obtained by transcranial electrical or magnetic
• stimulation or direct spinal cord stimulation

• If you are delivering 1 L of O2 and 1 L of air, what % O2 is
• being delivered?

• So there is 1 L of 100% O2 and 1 L of 21% O2.
•  100 + 21= 121
• 121 divided by 2= 60% O2

• You should also know how to do this with N2O
• (remember, there is no O2 in N2O).

• o  
• Monochromatic- possesses one wavelength

• o  
• Coherent- it oscillates in the same phase

• o  
• Collimated- exists as a narrow, parallel beam

• ·     
• Depends on wavelength, which is determined by
• the medium in which the laser beam is generated. 

• ·     
• A laser medium is a substance that can be
• stimulated to emit a stable state when pumped with an external energy
• source. 

• ·     
• Can be solid, gas, liquid, or
• semiconductor.  An example of this is
• that a medium of CO2 gas laser produces a long wavelength laser while a Yag laser (which is
• solid-state laser) results in a shorter wavelength. 

• ·     
• The longer the wavelength, the greater the
• absorption of water, and the less tissue is penetrated.  Therefore, the CO2 laser’s effects are much
• more localized & superficial than the Yag laser.  However, the solid-state lasers such as the
• Yag laser are more powerful than gas lasers.

o

• The fire triangle is depicted below. It
• demonstrates that no one person alone is responsible for fire prevention.  Fire prevention requires intraoperative
• collaboration with at least one of the other two professions.

• ·     
• The surgeon
• yields the ignition source.

• ·     
• Anesthesia
• controls the oxidizers (oxygen and
• nitrous).

• ·     
• RN
• personnel are frequently in control of the safe use of potential fuels (alcohol prepping solutions and
• sponges).

• ·     
• An oxidizer is a substance that will support the combustion of fuel. Most
• fuels burn only in the gaseous state and ignite only when sufficient vapors mix
• with oxygen. Heat produces these
• vapors by evaporating liquids or vaporizing solids. Although oxygen from the
• air combines with the fuels during surgery during a fire, the OR has other
• sources of oxygen.

• ·     
• Anesthesia requires the delivery of oxygen concentrations
• above 21%. Whenever and wherever the O2 concentration is above 21% = O2
• enriched environment. With increased O2 a fire is easy to ignite, it will burn
• faster and hotter, and it will be difficult to extinguish.

• ·     
• Oxygen is supplied from the anesthesia machine,
• which is a ventilator, wall outlet, or the gas cylinder.

• ·     
• O2 is heavier than air, it will collect in
• low-lying cavities/areas: open chest cavity or under the drapes.

• ·     
• Drape fabrics will absorb oxygen and retain it
• for some time.

• ·     
• Oxygen-enriched environment will also allow some
• materials (ie. plastic) to burn that would otherwise not normally burn at RA.

• ·     
• Oxygen for a fire can also be supplied from
• thermal decomposition of N2O. Heat
• from sources found in OR or fire will liberate oxygen from nitrous, allowing it
• to support combustion.

• ·     
• Within the context of surgical fires, any
• mixture of oxygen and nitrous is considered to be an oxygen-enriched
• environment.

• ·     
• In the event of a fire, the supply of nitrous as
• well as oxygen must be shut off quickly.

• ·     
• OR supplies that support combustion: ETT, O2
• catheters, surgical drapes, benzoin, alcohol cleansing solution,
• petroleum-based ointments (lacrilube)

• ·     
• Fuel is
• anything that can burn – Including almost anything that comes in contact
• with patients as well as the patients themselves.

• ·     
• Some more commonly found fuels in surgery
• include hair, GI tract gases (methane, hydrogen, hydrogen sulfide), drapes,
• gowns, sponges, breathing circuits, etc.

• ·     
• CDC recommends alcohol-based gel solutions for
• hand hygiene and alcohol-based chlorhexidine solutions for skin preps. Now they
• say the patient cannot be draped for 3 minutes – RNs should also ensure
• that there is no pooling of solution.

• ·     
• Potential for fire is augmented when the
• alcohol-based antiseptic is applied in ways that allows pooling (may not even
• see it because it under the patient). Sponges themselves will help to prevent
• that.

• ·     
• Providone-iodine solutions are also flammable.
• Similar cautions must be made during prepping.

• ·     
• Under the right conditions, some surgical
• ointments can burn. Some petroleum-based ointments used in oxygen-enriched
• environments will ignite when enough heat is present to cause vaporization.
• These materials must vaporize and mix with oxygen to allow ignition. Globs will
• not easily ignite because its mass absorbs considerable heat before
• vaporization occurs. However, thin layers have low mass per area and need less
• heat to cause vaporization, and are easier to ignite.

• ·     
• Water-based ointments (surgilube) will not burn
• easily. Head and neck surgery – may put surgilube in the patient’s hair.

• ·     
• Heat
• input from a variety of sources increases the oxidation rate of fuel, oxygen
• mixture until combustion will occur.

• ·     
• In addition to the overhead surgical lights,
• some of the other heat sources found in the OR include defibrillators, cautery
• units, heated probes, drills & burrs, fiberoptic light sources & the
• cables, and lasers. These sources produce temperatures from several hundred to
• a few thousand degrees Fahrenheit. (Enough to ignite most fuels.)

• ·     
• Incandescent sparks produced by electric cautery
• or high-speed drills and burrs can cause fires.

• ·     
• Lasers can case sparks when energy hits an
• instrument or the laser fiber itself may be damaged.

• ·     
• Even glowing embers of charred tissue can
• provide enough initial heat to ignite some fuels – especially when you are
• using oxygen around it.

• ·     
• A few seconds after deactivation, a heated
• cautery probe tip, a fiber optic cable tip, or a laser contact tip can retain
• enough heat to melt plastics or ignite fuels.

• ·     
• While these devices must be in contact with the
• material to heat it, a laser can heat from a few centimeters to several meters
• away. A fiber optic light source may take a minute or so to heat a drape to the
• point of combustion, while a laser can cause this almost instantaneously.

• ·     
• By ensuring that these heat sources are not
• directed towards or allowed to come in contact with the fuel, the OR staff can
• prevent these fires. 

• ·     
• Static electricity

• ·     
• Electrical equipment: electrosurgical unit
• (cautery near distended bowel), lasers (used near ETT)

• 54.  safety devices on
• anesthesia machine that prevent anesthetic agent overdoses

Capnography and anesthetic gas measurement

n  Vigilance

• n  Laser
• safety protocols

• n  Allow
• surgical preps to dry

• n  Minimize
• oxygen concentration

1. Flammable agent (fuel)

•             a.
• anesthetic agents

•             b. bowel gas:
• methane, hydrogen, hydrogen sulfide

2. A gas that supports combustion

•             a.
• operating room supplies: o2 catheters, surgical drapes, petroleum based
• ointments, petroleum based lacrilube

•             b. oxygen
• and nitrous oxide

3. Source of ignition

• a. static
• electricity: decrease by maintaining relative humidity
•  b. electrical equipment:electrical surgical
• units, cautery, laser, distended bowel, laser near ETT

Patients eyes should be taped and operating room personel should wear protective eyeglasses

• LASER =
• Light amplification by stimulated emission of radiation

 

• ·     
• Lasers different from normal light in 3 ways:

• o  
• Monochromatic- possesses one wave-length

• o  
• Coherent- it oscillates in the same phase

• o  
• Collimated- exists as a narrow, parallel beam

 

 

• ·     
• LASER
• = Light amplification by stimulated emission of radiation

• o  
• Use and s/e of a laser depends on wave length,
• which is determined by the medium in which the laser beam is generated

• o  
• Laser medium is substance that can be stimulated
• to a meta stable state when pumped with external energy source- either a solid,
• gas, liquid or semiconductor

• § 
• Medium CO2 gas laser produces a long wavelength laser while a YAG
• laser, which is a solid-state laser, results in a shorter wavelength.

• § 
• The longer the wavelength the greater the absorption of
• water and less tissue is penetrated. Therefore, the CO2 laser effects are much
• more localized and superficial than YAG. 
• Shorter wavelength lasers including the YAG are more powerful but will
• hit a larger area.

• o  
• Thermal
• trauma- misdirected beams potential risk for patient and OR staff- why we wear
• goggles too, skin trauma dependent on energy and wavelength of laser, varies
• from reddening to blistering and charring

• o  
• Eye
• injury- see question 19 for eye safety, eye is especially at risk because
• lasers radiation is coherent and all energy can be focused on very small
• portion of cornea or retina: CO2 injures cornea YAG injures retina, NO
• petroleum based ointments during laser procedures because they can cause burns

• o  
• Perforation
• of organs or vessels- usually d/t misdirected laser beams, can result in
• bleeding or edema that may not appear for hours or days after surgery

• o  
• Gas
• embolism- rare but potentially fatal

• Pollution- lasers create smoke with toxic gases
• and vapors, CO2 laser causes most smoke, high concentrations of smoke cause
• ocular and upper respiratory irritation, some lasers may be used with portable
• smoke evacuators, special filtration masks may be required for staff 

• o  
• during
• certain procedures to filter out airborne particles and airborne particles

• o  
• Fire

• Endotracheal
• tubes support combustion-some are more resistant that others but there isn’t
• one that prevents it all together 

• Polyvinyl
• is what is typically used

• Also
• a metallic tape that can be used- would need to prep ETT in AM/before surgery

·      Inspired O2 kept low

• o  
• Need
• to change O2 analyzer to allow you to administer <30%

• o  
• Make
• sure your anesthesia machines has air hooked up to it

• ·      Nitrous Oxide NOT used- nitrous
• supports combustion

·      ETT cuff filled with fluid

• o  
• Fill
• cuff with saline dyed with methylene blue so can recognize if cuff has been
• pierced

• ·      Laser intensity and duration
• limited

·      Saline-soaked pledgets in airway

• Don’t remove lift drapes into air
• re can fuel fire-pull off horizontally! TAKE OUT ETT AND REINTUBATE!

• ·      Micro-shock-results from current
• being supplied to externalized conductor such as saline filled catheter or
• packing wire BUT only effects patients that are electrically susceptible ie pt
• with CVL or pacemaker, results in internal injury

• o  
• Very
• small amount of current can cause damage 100 microamp = vfib (unlike with macro need 100-300 milliamp)

• o  
• Total
• leakage of OR equipment must be under 10 microamps to keep patient from being
• affected

• ·      Cautery- very frequently used by
• surgeons for cutting and tissue coagulation

• o  
• Generate
• ultra high frequency current that passes from cautery tip through patient and
• exits via grounding pad

• o  
• May
• cause shock, burns, explosions, arrhythmias, and disturbance in pacemaker
• function

• §  Smoke inhalation- unknown if its
• harmful but recommended that it be drawn out with suction

• §  Extensive tissue burns- patients
• are wet with blood and/or fluid and make electrical contacts with electrically
• conductive materials including OR table, monitoring electrodes, surgical
• retractors, stirrups = DANGEROUS PATHWAY FOR CURRENT won’t be shocked re
• transformer but can be burned if touching one of these electrically conductive
• materials/metal

• o  
• GROUNDING
• PAD (Bovie)- to return high current from unit to low current and return it back
• to cautery unit,

• Correct
• placement = current dispersed over large area 

• If grounding pad buckles energy
• will go to small area and cause burn            

• ·     
• 2 types of cautery: unipolar and bipolar

• o  
• Unipolar

• § 
• Most commonly used- to cauterize vessels

• § 
• Grounding pad placed on patient- if have to use
• with pacemaker make sure pad is not near pacemaker, place it as far away as
• possible, same idea if patient has any metal in body  

 

 

• o  
• Bipolar

 

 

• §  Used
• for less vascular tissue,

• § 
• No bovie/grounding pad

• § 
• Used especially for patients with AICD (automatic implantable
• cardioverter defibrillator) or pacemaker re current will stay LOCALIZED, will
• only go from cautery pen and back to cautery unit

 

Principles of Electricity                The Ohm’s law we know

Ohm’s Law: E=I x R                      BP = CO x SVR                   

• E= electromotive
• forces (volts)      BP = volts

I= current (amperes)                     CO = current

• R= resistance (ohms)        SVR
• = resistance to the forces opposing the flow of electrons

 

• Electrical devices in surgery have the potential to
• cause electrocution and burns in patients and OR staff. It is our
• responsibility to have some basic knowledge.

• Ohm’s law correlates the flow of electricity, the
• applied electrical pressure and the resistance to this flow.

• In order for electricity to occur electrons must move
• from an area of high concentrations to low area of concentration. A potential difference
• needs to exist between these two points. (Expressed in volts)

• ·      Micro-shock-results from current
• being supplied to externalized conductor such as saline filled catheter or
• packing wire BUT only effects patients that are electrically susceptible ie pt
• with CVL or pacemaker, results in internal injury

• o  
• Very
• small amount of current can cause damage 100 microamp = vfib (unlike with macro need 100-300 milliamp)

• o  
• Total
• leakage of OR equipment must be under 10 microamps to keep patient from being
• affected

• ·      - very frequently used by
• surgeons for cutting and tissue coagulation

• o  
• Generate
• ultra high frequency current that passes from cautery tip through patient and
• exits via grounding pad

• o  
• May
• cause shock, burns, explosions, arrhythmias, and disturbance in pacemaker
• function

• §  Smoke inhalation- unknown if its
• harmful but recommended that it be drawn out with suction

• §  Extensive tissue burns- patients
• are wet with blood and/or fluid and make electrical contacts with electrically
• conductive materials including OR table, monitoring electrodes, surgical
• retractors, stirrups = DANGEROUS PATHWAY FOR CURRENT won’t be shocked re
• transformer but can be burned if touching one of these electrically conductive
• materials/metal

• o  
• GROUNDING
• PAD (Bovie)- to return high current from unit to low current and return it back
• to cautery unit,

• Correct
• placement = current dispersed over large area

Unipolar 

• § 
• Most commonly used- to cauterize vessels

• § 
• Grounding pad placed on patient- if have to use
• with pacemaker make sure pad is not near pacemaker, place it as far away as
• possible, same idea if patient has any metal in body  

• o  
• Bipolar

• §  Used
• for less vascular tissue,

• § 
• No bovie/grounding pad

• § 
• Used especially for patients with AICD (automatic implantable
• cardioverter defibrillator) or pacemaker re current will stay LOCALIZED, will
• only go from cautery pen and back to cautery unit

Principles of Electricity                The Ohm’s law we know

Ohm’s Law: E=I x R                      BP = CO x SVR                   

• E= electromotive
• forces (volts)      BP = volts

I= current (amperes)                     CO = current

• R= resistance (ohms)        SVR
• = resistance to the forces opposing the flow of electrons

 

• Electrical devices in surgery have the potential to
• cause electrocution and burns in patients and OR staff. It is our
• responsibility to have some basic knowledge.

• Ohm’s law correlates the flow of electricity, the
• applied electrical pressure and the resistance to this flow.

• In order for electricity to occur electrons must move
• from an area of high concentrations to low area of concentration. A potential difference
• needs to exist between these two points. (Expressed in volts)

DIRECT CURRENT (DC):

• ·     
• Direct flow of electrons in the same direction.
• (ex: Flashlight battery, laryngoscopes, twitch monitors)

 

ALTERNATING CURRENT (AC): 

• ·     
• Alternating flow of electricrons occurs in 1
• direction then reverses itself at regular intervals. Electrical Power Company. In OR, most
• current is AC.

• ·     
• In the US, utility companies supply electrical energy
• in the form of ACs of 120volts at a frequency of 60Hz.  

 

• *Either
• of these types of current can be pulsed or continuous in nature.

 

• Ohm’s law is accurate when applied to DC circuits. But with
• AC circuits, the situation is more complex because the flow of the current is
• opposed by more complicated form of resistance called impedance. Impedance is
• the sum of the forces that oppose electron movement in the AC circuit. It
• consists of resistance (Ohm’s) but also takes capacitance and inductance into
• account.

• Hertz = frequency in cycles per second at which the AC
• current reverses direction ( # of times the AC reverses itself in 1 second). 60
• hertz in USA.  As frequency increases,
• impedance to flow decreases and more current is allowed to pass.

• The SI unit of electromotive force, the difference of
• potential that would carry one ampere of current against one ohm resistance

flow of electrons/sec past a given point. When this happens, heat & light are produced

• Resistance includes forces that oppose current flow or is an impendence to flow. Higher resistance, less amount of current will flow
• If short circuit, there will be 0 impedance.

• ·     
• Whereas electrical
• power is grounded in the home, it is usually UNGROUNDED in the OR.

• ·     
• In the home, electrical
• equipment may be grounded or ungrounded but it should ALWAYS BE GROUNDED in
• the OR.

• ·     
• In a grounded power system, it is possible to
• have either grounded or ungrounded equipment, depending on when the wiring was
• installed and whether the electrical device is equipped with a three prong plus
• containing a ground wire.

• ·     
• Electrical 
• contacts w/ground can cause injury when they complete the circuit ( that
• permits the pt completes it) but now we isolate the electrical power instead of
• being grounded, it is UNGROUNDED POWER

• ·     
• In the OR, numerous electrical devices, together
• w/power cords and puddles of saline solutions on the floor, make an
• electrically hazardous environment for both patients and personnel.

• ·     
• To
• provide an extra measure of safety from macroshock, the power supplied to most
• ORs is ungrounded!!

• ·     
• The 120 volt potential difference exists only
• between the two wires of the isolated power system (IPS) but no circuit exists
• between the ground and either of the isolated power lines.

• ·      The isolation transformer allows the
• electrical power to be ungrounded in the OR. The electrical power in the OR
• comes from a hospital source, the usually originates from a connection to an AC
• from the local power company. After arrival to the OR, electrical power is
• modulated, isolated, and dispensed to electrical outlet in the room by
• secondary coils. Here, you will either have one or more large isolation
• transformers. Each isolation transformer is required to have a line isolation
• monitor, which is a simple electrical current meter that demonstrates the
• isolation of the transformer’s out power from the ground. If there is a short
• circuit, you will see the monitor fluctuate, and it will shut off the power.
• The line isolation monitor verifies that the power lines from the transformer
• are indeed isolated from the ground. It is connected to both sides of the
• isolated power outlet (the primary and secondary coils) and is set to alarm and
• shut off the power when either side has an impedance to the ground of less than
• 25,000 ohms, or when the max current reaches 2 milliamps from a short circuit.
• So the line isolation monitor is insensitive to currents below 2 milli amps.
• Therefor it will provide not protection against Micro Shock, it only protects
• against macro shock.

• ·      Dripping saline or water onto the
• extension cords or outlets,

• ·      Micro shock- Result when the electrical
• current is accidently applied to an external conductor such as a saline filled
• catheter, or an electrical pacing wire. This only concerns patients that are
• electrically vulnerable: i.e. patients with a pacemaker, central lines.
• Measured in Micro ampules. Very small amounts of current can cause damage. So in
• order to prevent this, the total leakage of OR equipment can only be 10 micro
• amps.

• o  
• 100
• micro amps – Causes V Fib

• ·      Macro shock- describes the effects of
• current applied to the body through intact skin. The flow of current takes the
• path of least resistance. Which would be the great vessels, nerves, and
• muscles. The units of measure associated with macro shock are milli ampules.
• Occurs from currents that rise from equipment failure, unsafe design, or
• misuse.

• o  
• 1
• milli amp (mA) – Perception

• o  
• 5 mA
• – Max harmless current

• o  
• 10-20
• mA – “let go” current

• o  
• 50 mA
• – loss of consciousness

• o  
• 100-300
• milli amps – V Fib, respiratory center
• remains intact

• o  
• 6000
• mA – complete physiologic damage

 

• Kathy said to remember this number: 100-300 milliamps (macroshock) will cause V
• Fib, respiratory center intact versus 100 microamps
• to cause V Fib

 

• In order to prevent microshock, the total leakage of OR
• equipment must be 10 microamps, so if
• we have a little current going on, as long as it’s under 10 microamps the patient will not be
• affected

• 74% of all cases of surgical fires have been in an oxygen
• enriched environment, a common contributor during head and neck surgery is the
• delivery of large concentrations of oxygen via a facemask

 

• Drapes covering the patient result in accumulation of
• concentrated oxygen under them, referred to as tenting; therefore, in an O2
• rich environment, application of an ignition source (such as the electrocautery unit, defibrillator, a hot fiber optic light
• source, or surgical laser) can regularly ignite this

 

Surgeon wields ignition source

 

• Static electricity in the past hospitals would try to
• decrease static electricity by maintaining humidity at 50%, gets to grade point
• where instruments aren’t sterile anymore

 

• Electrical equipment that is found in the OR- includes
• electrosurgical units (cautery), lasers

• nvolved in disinfection and sterilization of devices and
• procedures

• : regulates chemical germicides used on medical devices,
• also requires a manufacturer of reusable product to provide adequate
• instructions on cleaning and disinfecting

• regulates occupational exposure to chemical disinfectants
• and sterilizers

• recommends broad strategies to prevent transmission of an
• infection in the health care environment

•  Most resistant type
• of germs: bacterial spores (some of which are resistant to chemical and
• physical stresses) Hep B and HIV are the least resistant to chemicals

• a substance that may be applied to living tissue, it has
• antimicrobial activity

• agent that prevents bacteria growth but it will not kill the
• bacteria

• process by which contaminated items are rendered safe for
• personnel who are not wearing protective attire

• A. 
• Reasonably free of (probably) transmitting infection

• B. 
• Reduction of microbial contamination to an acceptable level

• C. 
• Any process that  Eliminates harmful
• substances

• chemical germicide that is formulated to be used solely on
• inanimate objects (NOT HUMANS!)

3 Types of Disinfectants

• 1) High level- kills all organisms
• including bacterial spores and certain viruses; most of these can produce
• sterilization with sufficient contact time

• 2) Intermediate Level- kills
• bacteria including TB, some fungi, most viruses, but NOT bacterial spores

• 3) Low Level- kill most bacteria,
• NOT TB, some fungi, viruses, and spores

destruction of all viable forms of microorganisms

• 6 methods of sterilization “that
• you should be familiar with”

• 1) Pasteurization- equipment is
• immersed in water at an elevated temp for a given period of time. It is a
• disinfecting process that cannot be depended on for sterilization ex.
• ventilator bellows, laryngoscope blades (first step in sterilization process,
• this isn’t the only way blades are cleaned)

• Advantage to this method: lower
• temperatures: there’s less damage to the equipment and also no toxic fumes or
• residues

• 2) Steam Sterilization-aka:
• autoclaving: uses saturated steam under pressure, it will kill all bacteria,
• spores, and viruses; this is the method that is used in OR to clean ALL
• surgical equipment

• 3) Chemical Disinfection and
• Sterilization- utilizes liquid chemical agents and is often performed by
• soaking an item in the solution; it is useful for heat sensitive equipment

• Disadvantage: chemicals can be
• absorbed into the items and cause harm to the patients, cannot be used for all
• types of equipment, sterility is not guaranteed, some solutions aren’t safe for
• tissue, will have an unpleasant odor and you will need to avoid prolonged skin
• contact or inhalation of these vapors

• 4) Gas Sterilization- kills
• bacteria, spores, fungi, and viruses, it is flammable, and is a more complex
• and extensive process, it is restricted to objects that might be damaged by
• heat or excessive moisture, other complications: due to residual left on
• sterilized items that may cause skin reactions or laryngeal/tracheal
• inflammation- ethylene oxide

• 5) Radiation Sterilization- gamma
• rays; used for sterilizing disposable products from manufacturers, products are
• pre-packaged before treatment and will remain sterile indefinitely until
• package is opened (ex. ETT)

• 6) Gas Plasma Sterilization- uses
• gaseous chemical germicide and gaseous plasma, it is used on packaging
• materials, plastic, and stainless steel instruments and the one you’re going to
• hear is called the Sterrad system

• 1.    
• Alcohol- intermediate level germicide, it will
• kill most bacteria, but not spores, the effect of this is limited due to the
• rapid vaporization and it’s also flammable; ex chlorohexidine

• 2.    
• Iodophores- combination of iodine and
• solubilizing agent; principally used at antiseptic

• 3.    
• Cydex- high level disinfectant that is used in a
• 1% concentration and it MUST be rinsed thoroughly because it’s a physical
• irritant and will cause patient issues

unipolar

-most commonly used in the OR

• current flows thru pt, to a grounding pad, then back to
• cautery unit itself

-used to cauterize vessels

• -if using this type with a pt that has a pacemaker, place
• bovie pad away from pacemaker (on thigh for example)

• -can’t use the grounding pad if the patient has metal in
• their body

bipolar

-used for less vascular tissues

-no grounding pad used with this type

-recommended for a pt with an AICD or PM

-current is localized and does not go thru pt’s body

-current goes from cautery pen back to the unit

capnometer

-O2 analyzer

-pressure monitor with high and low airway pressure alarms

-pulse ox

-respiratory volume monitor (spirometer)

• emergency ventilation equipment (ambu bag and mask,
• intubating stylets)

• -high pressure system (check O2 cylinder supply- should be
• at least 1,000 psi, check central pipeline pressures- should be 50-55 psi)

• -low pressure system (check vaporizer levels and fill if
• needed, test flowmeters- attempt to create a hypoxic mixture with O2 and N20)

• -check scavenging system (check connections and adjust waste
• gas vacuum- bobbin should be inbetween 2 white lines)

• -calibrate O2 monitor (make sure low O2 alarm is working,
• test RA and > 90%)

-check that breathing circuit is complete and undamaged

• -verify CO2 absorbent is adequate (at least ¾ white, a
• little purple is ok)

• -perform breathing system leak check (close APL valve and
• occlude Y piece, pressurize breathing system to 30 cm H20 with O2 flush, ensure
• pressure remains fixed for at least 10 secs, then open APL valve and ensure
• pressure decreases)

• -test vent (place a second breathing bag on Y piece and
• switch to auto (vent) mode, make sure bellows deliver appropriate tidal volume
• and that bag inflates, watch bellows on expiration and ensure bag deflates)

-ensure unidirectional flow valves are working

• -then switch back to manual (bag mode) and ventilate
• manually- assure inflation and deflation and feel appropriate resistance and
• compliance

-check monitors (see above)

• -check final status of machine (vaporizers off, APL valve
• open, selector switch to “bag,” flowmeters at minimum, suction ready, breathing
• system ready to use

AMBU bag

• Oxygen source separate from the
• anesthesia machine and pipeline supply (AKA O2 cylinder with regulator; also
• need means to open cylinder valve)

• ·     
• Chronic fatigue

• ·     
• Work schedules

• ·     
• Critical patients

• ·     
• Fears of litigation

• ·     
• Productivity demands

Lack of control

• ·     
• Acknowledges role of internal and external
• stressors

• ·     
• Set objectives

• ·     
• Raise awareness and educate

• ·     
• Alert students and CRNA’s

• ·     
• Wellness = “state of complete physical, mental,
• and social well-being”

• o  
• Not only absence of illness but awareness and
• understanding

• ·     
• 13.4 million alcohol problem

• ·     
• 3 million abused/dependent on drugs

• ·     
• Chemical dependency = Is defined as a substance
• use disorder characterized by an inability or unwillingness to terminate use in
• spite of serious negative consequences

Signs/Symptoms of abuse:

• ·     
• Frequent breaks

• ·     
• Extra call shifts

• ·     
• Increasing tardiness

• ·     
• Gradual decline in performance

• ·     
• Signs out more narcotics that other providers

• ·     
• Inappropriate drug choices

• ·     
• Difficulty with authority

• ·     
• Forgetful, unpredictable, confused

• ·     
• Frequent illnesses

• ·     
• Exhibits dishonesty

• ·     
• Elaborate excuses

• ·     
• Suffers from tremors or “Monday morning shakes”

• ·     
• Appears intoxicated at social functions

• ·     
• Discovered comatose or dead

Wellness Program Includes:

• ·     
• Assess nature and impact

• ·     
• Education

• ·     
• Treatment modalities

• ·     
• Advocating research

• ·     
• Assisting individuals or organizations

• Another place oxygen goes is to our flow meters flow meters are calibrated
• for specific gases as Flow rate depends on gas viscosity at how low laminar
• flow and density at high turbulent flow. 
• To minimize the effect of friction b/w these (gases and tube wall)
• floats are designed to rotate constantly to keep them in the center of the tube

• Some glow meters have 2 glass tubes, one for low, one for high.  The two tubes are in series and controlled by
• one nob.

Dual taper design can allow for reading of both high and low flows.

Malfunctions include:

Debri in flow tube

Vertical flow tube misalignment

Sticking or concealment of flow meter at top of tube

• Flow meter sequence a potential cause of hypoxia in the event of a flow
• meter leak, a potentially dangerous arrangement results when nitrous is located
• in the downstream position.  The SAFEST
• configuration exists when o2 is located in the downstream position. (nearest
• the vaporizer)  ( This was a mid term
• question!)

• Flow rate depends on gas viscosity at how low laminar flow and density at
• high turbulent flow.  To minimize the
• effect of friction b/w these (gas and tube wall) flows are designed to rotate
• constantly to keep them in the center of the tube

• Fabious has convention flow valve but Electronic flow sensor and digital
• displays instead of gas flow tubes

Flow tube shows additive gas flow rate

Pathways of O2

1 supply pneumatically powered bellows ventilator

• 2 Via a regulator and an auxiliary O2 flow meter to be connected to a nasal
• cannula, ambu bag, etc

3. To the O2 low pressure alarm sensor

4. Pressure sensitive shutoff valve (fail safe) valve

5. To the O2 flush control valve

6. O2 flow meters

Cylinder

H          Air




Cylinder


Air


O2


N2O




E


1900 PSIG (625L)


1900 PSIG ( 660L)


745 PSIG ( 1590 L)




H


2200 PSIG (6550L)


2200 PSIG (6900L)


745 PSIG (15800L)




 

E

Pipeline- 50-55 PSIG

High-pressure systems:

• 1.    
• Cylinders

• 2.    
• Hanger Yokes

• 3.    
• Cylinder primary pressure regulator

• 4.    
• Cylinder pressure gauge

• 5.    
• Check Valve Assembly

• 1.)  Cylinder
• supply source (45 psig)

• 2.)  Pipe
• line ( 50 -55)

• 3.)  O2
• pressure failure devices

• a.    
• O2 fail safety

• b.    
• O2 failure alarms

• 4.)  O2
• flush valve

• 5.)  Flow
• control valve

• 1.)  Flow
• meter indicator and tubes

• 2.)  Check
• Valve

• 3.)  Low
• flow pressure reducer regulator (if present)

4.)  Vaporizer

• 5.)  Common
• Gas outlet

Part of the intermediate pressure circuit

• Ø  Allow
• direct communication between O2 high-pressure
• circuit and low-pressure circuit

• Ø  Enters
• low-pressure downstream of vaporizers

• Ø  Delivers
• 100% O2 at a rate of 35-75L/min

• Ø  High-pressure
• O2 source for jet ventilation

 

Ø  Hazards

• l  Valve
• sticks

l  Awareness

l  barotrauma

• Index
• pins- safety (2&5 vs 3&5) pins are on the yolk, holes are on the tank

The Pin Index Safety System- used to prevent mix up of gases

• 1.    
• 2 & 5: oxygen

3 & 5: nitrogen oxide

• Issue:
• multiple washers will make the pins obsolete, and you can still have an error

Fail safe valve

 

• These prevent the delivery of hypoxic (<21% O2) gas
• concentrations.

Fail safe device

• ·     
• Permits the flow of other gases (N20, air and
• volatile) only if there is sufficient oxygen pressure to prevent the
• administration of a hypoxic mixture of gases.

• a.  
• Low oxygen pressure alarm

•                                 
• i.     Detects
• oxygen supply failure at the common gas inlet

• b.  
• Low vent pressure alarm

•                                 
• i.     Causes

• 1.  
• minimum airway pressure, low airway pressure,
• ventilation failure, apnea, cycling, pressure failure, disconnect, ventilator
• disconnect, minimum ventilatory, ventilation pressure, threshold pressure,
• low-pressure, peak airway, fail-to-cycle, low pressure, low circuit pressure

•                               
• ii.     alarm
• is activated if the pressure detected does not exceed a preset minimum within a
• fixed time

• a.  
• activated by a pressure that falls below
• atmospheric pressure by a predetermined amount. Subatmospheric pressure can be
• generated by a patient attempting to inhale against a collapsed reservoir bag
• or increased resistance; a blocked inspiratory limb (during the ventilator’s
• expiratory phase); a malfunctioning active closed scavenging system; suction
• applied to a nasogastric tube placed in the tracheobronchial tree or to the
• working channel of an endoscope passed into the airway; a sidestream gas
• analyzer; or the refilling of a hanging bellows ventilator bellows

• a.  
• Switch over to cylinder and if that doesn’t work
• start to bag patient and obtain another cylinder for O2

• a.  
•  Even in the presence of complete obstruction,
• this alarm will not be activated if the peak inspiratory pressure does not
• reach the set limit. High compliance, low resistance, leaks, low inspiratory
• flow rates, high respiratory rates, low I:E ratios, low tidal volumes, and low
• fresh gas flows can all decrease the peak inspiratory pressure so that there is
• no alarm condition. During pressure control ventilation, the inspiratory airway
• pressure is preset and thus cannot act as a warning of tracheal tube occlusion.